The term “door latch” used herein refers to the mechanism mounted on the edge of a vehicle door which engages with a striker mounted on the door frame in order to “latch” the door in the closed position. The terms “unlatching” and “unlatch” refer to operating the door latch in a manner to disengage from the striker so the door can be swung open. The term “locking” refers to operating the door latch so that it cannot be opened from outside the vehicle by an unauthorized person. The term “unlocking” refers to operating the door latch so that the door latch can be readily unlatched from outside the vehicle by any person.
Modern motor vehicles have a remote entry fob carried by the driver for operating the side door latch from a distance. In some vehicles, the radio frequency signal from the fob will merely unlock the door latch so that the user can lift a door handle to unlatch the door latch. In other vehicles, the radio frequency signal from the fob will unlatch the door latch so that the energy stored in the weather strip will pop the door open without the user having to lift a door handle.
A problem with the use of a fob to operate the latch, by either unlocking a door latch or unlatching the door latch, is that the fob can fail to work if the battery is weak or the fob becomes damaged, for example by moisture. When the fob fails, the user will enter the vehicle by using a key to unlock the door latch via a key cylinder mounted on the side door. Or in some cases, the side door will have a digital key pad for unlocking the door.
It would be desirable to improve the aesthetics and reduce the cost of the vehicle by eliminating the need for either a key cylinder or key pad on the side door. However, this would leave the user unable to gain entry to the locked vehicle in the event of failure of the fob.
Accordingly, the present invention provides a new and improved method for operating a side door latch without the use of either a fob or a key cylinder or a key pad mounted on the side door.
In addition, because of the challenge of training vehicle users to understand the nuances of a new door latch control system, it would be desirable to provide an improved method for instructing the vehicle user as to the nature of the problem that has occurred and giving the user advice as to how to repair the problem. In particular, the driver should be advised to seek a repair of the fob.